Analysis of biological samples, such as fecal material, requires appropriate collection methods, optimum storage conditions, and careful handling during filtration and concentration to maintain the integrity of the microorganisms and analytes present in the sample, and to prevent the biohazardous components of the sample from contaminating the contact environment, including the equipment and the operator. Current practice involves collecting a sample, such as fecal material, in a specimen jar with a fixative liquid. The specimen jar with the sample is then transported to a laboratory where the sample is filtered and concentrated before it can be used for subsequent diagnostic and analytical procedures. The filtration of the sample involves removing the sample from the sample jar and transferring the sample to a filter unit with a filtrate collection tube. More than one filter unit may be used during the filtration process. Large debris and sediments may be removed first by passing the sample through a filter unit with large pore size followed by filtration through a filter unit with smaller pore size. The sample may be passed through the filter unit and into the collection tube via gravitational force and/or centrifugal force.
One example of a collection tube with a filter unit is illustrated in U.S. Pat. No. 6,296,763. A double receptacle filtration assembly has two open mouthed receptacles, a sample receptacle and a filtrate collection receptacle, configured to couple together through a hollow stopper containing a tubular filter. The sample is transferred from a specimen jar to the sample receptacle of the filter unit using a transfer device. The sample receptacle is then attached to the filter and the filtrate collection receptacle. The filter unit with the two receptacles attached is transferred to a centrifuge for filtration.
The inventors herein have recognized problems with the abovementioned filter unit, including additional handling of the biological sample required for transferring the sample from a separate sample specimen jar using a collection/transfer device into the filter unit, increasing the possibility of contamination of the contact equipment and operator. Also, additional reagents may be added to the sample and the sample filtrate for preserving and processing the sample, increasing the possibility of sample degradation and/or contamination of the contact environment.
To minimize sample handling during filtration and concentration of a biological sample, the inventors propose a sample collection, filtration and processing apparatus with a filter unit which may be coupled to a sample collection tube with an integrated sample collection device, and to a sample processing tube. One example of the apparatus may include a sample collection tube containing a transportation liquid with a first open end and a second open end opposite the first open end. The sample collection tube first open end may be configured to couple to a first removable cap. The first removable cap may have an integrated sample collection device. The apparatus may include a sample processing tube containing a processing liquid with a sample processing tube first open end and a sample processing tube second closed end opposite the processing tube first open end. The apparatus may include a matched filter unit with a first open end and a second open end opposite the filter unit first open end. The filter unit first open end may be configured to couple to the collection tube first open end, and the filter unit second open end may be configured to couple to the processing tube open end.
In one example of using the above described sample collection, filtration, and concentration apparatus, the sample may be collected with a collection device coupled to a first removable cap. The first removable cap may couple to a sample collection tube first open end, where the coupling may introduce the sample and the sample collection device into a transport liquid in the sample collection tube. A matched filter unit may be coupled to an open end of a processing tube containing a processing liquid to form a filtration-processing unit, followed by removal of the first removable cap from the sample collection tube first open end. The filtration-processing unit may subsequently be coupled to the sample collection tube first open end such that the filtration-processing assembly may align with and close the collection tube first open end. The sample may now be filtered from the sample collection tube, through the filter unit and in to the processing tube.
Thus, the sample collection, filtration, and processing apparatus described above enables direct collection and transfer of a sample to the sample collection tube using the integrated sample collection device of the apparatus, eliminating the need for a separate sample specimen jar and additional transfer device. The sample collection tube of the apparatus containing a pre-measured volume of a transport liquid and the processing tube containing a pre-measured volume of processing liquid, eliminates the need to introduce additional reagents into the apparatus, further reducing sample handling and contamination.